Commit 83540fbc authored by Jann Horn's avatar Jann Horn Committed by Steven Rostedt (VMware)

tracing/perf: Use strndup_user() instead of buggy open-coded version

The first version of this method was missing the check for
`ret == PATH_MAX`; then such a check was added, but it didn't call kfree()
on error, so there was still a small memory leak in the error case.
Fix it by using strndup_user() instead of open-coding it.

Link: http://lkml.kernel.org/r/20190220165443.152385-1-jannh@google.com

Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 0eadcc7a ("perf/core: Fix perf_uprobe_init()")
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarJann Horn <jannh@google.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent b689269b
...@@ -299,15 +299,13 @@ int perf_uprobe_init(struct perf_event *p_event, ...@@ -299,15 +299,13 @@ int perf_uprobe_init(struct perf_event *p_event,
if (!p_event->attr.uprobe_path) if (!p_event->attr.uprobe_path)
return -EINVAL; return -EINVAL;
path = kzalloc(PATH_MAX, GFP_KERNEL);
if (!path) path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path),
return -ENOMEM; PATH_MAX);
ret = strncpy_from_user( if (IS_ERR(path)) {
path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX); ret = PTR_ERR(path);
if (ret == PATH_MAX) return (ret == -EINVAL) ? -E2BIG : ret;
return -E2BIG; }
if (ret < 0)
goto out;
if (path[0] == '\0') { if (path[0] == '\0') {
ret = -EINVAL; ret = -EINVAL;
goto out; goto out;
......
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